Carlow weather in September

In September, Carlow sees average daytime highs of 16°C and overnight lows near 10°C, with 62 mm of rain across 10.9 wet days and about 12.4 hours of daylight. It is the 4th-warmest and 10th-wettest month of the year here.

Highs ease over the month, from about 18°C in the first days to 15°C by the end. The sky is clear or mostly clear about 8% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 30 min at the start of September to 11 h 24 min by month's end. Set against the rest of the year, September is Carlow's 9th-clearest and 9th-windiest month. For the whole year in context, see Carlow's year-round climate.

Daytime high
16°
4th warmest
Overnight low
10°
9th coldest
Rainfall
62 mm
10.9 wet days
Daylight
12 h 24 min
6:10 AM – 6:34 PM
Cloud cover
78%
9th clearest
Wind
13 km/h
9th windiest
Solar energy
2.81 kWh/m²
Travel score
4.8
out of 10

Carlow is county town of County Carlow, Leinster, Ireland.

Air quality
Good
PM2.5 7.6 µg/m³ · 2019
Density
219/km²
people per km²

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 18°C in the first days to 15°C by the end.

A typical September day in Carlow reaches about 16°C in the afternoon and slips back to 10°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 14°C and 19°C. Set against its neighbours, September runs about 2°C cooler than August and about 3°C warmer than October.

10°15°20°25°151015202530
Avg high (°C)Avg low (°C)
11811
21811
31810
41810
51710
61710
71710
81710
91710
101710
111710
121710
131710
141710
151710
16169
17169
18169
19169
20169
21169
22169
23169
24169
25169
26159
27159
28159
29159
30158

How September really feels in Carlow

Once humidity and wind are folded in, September averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Carlow weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 7112.80.57.91.1
Feb / 5811.40.89.51.3
Mar10° / 5911.50.611.52.0
Apr12° / 6812.7013.62.9
May15° / 6712.9015.54.0
Jun17° / 10°7111.6016.55.1
Jul19° / 12°6712.7016.15.4
Aug18° / 12°7311.7014.55.5
Sep16° / 10°6210.9012.44.8
Oct13° / 8012.1010.33.4
Nov10° / 7912.10.18.42.0
Dec / 7812.60.57.41.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 8% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 13% of September, with mostly cloudy or overcast conditions the remaining 80%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
12080
22080
31981
41981
51981
61981
71981
81981
91981
101981
111981
121981
132080
142179
152179
162179
172179
182179
192278
202278
212179
222179
232179
242179
252179
262080
272080
282179
292278
302179

Chance of precipitation in September

Any precipitation

Carlow gets around 62 mm of rain over 10.9 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 36% and peaks near 41% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
129
229
330
430
531
632
733
833
934
1035
1135
1236
1336
1436
1536
1636
1736
1836
1937
2037
2137
2238
2339
2439
2540
2640
2741
2841
2941
3040

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 83% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
177203
277203
377203
478193
578193
678193
778193
879183
979183
1080173
1181172
1282162
1382162
1483152
1584151
1684151
1785141
1885141
1985141
2086140
2186140
2286140
2386140
2487130
2587130
2687130
2787130
2888120
2988120
3089110

Wind in September

Winds average 13 km/h in September.

Across September, daily wind ranges from about 12 km/h on the calmest days to 13 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
112light breeze
212light breeze
312light breeze
413light breeze
513light breeze
613light breeze
713light breeze
813light breeze
913light breeze
1013light breeze
1113light breeze
1213light breeze
1313light breeze
1413light breeze
1513light breeze
1613light breeze
1713light breeze
1813light breeze
1913light breeze
2013light breeze
2113light breeze
2213light breeze
2313light breeze
2413light breeze
2513light breeze
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 30 min at the start of September to 11 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 126 minutes over September. Sunrise moves from 5:44 AM to 6:35 AM, and sunset from 7:11 PM to 5:59 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.55:447:11
213.45:457:09
313.35:477:06
413.35:497:04
513.25:517:02
613.15:526:59
713.05:546:57
813.05:566:54
912.95:586:52
1012.85:596:49
1112.86:016:47
1212.76:036:44
1312.66:056:42
1412.56:066:39
1512.56:086:37
1612.46:106:34
1712.36:126:32
1812.36:136:29
1912.26:156:27
2012.16:176:24
2112.16:196:22
2212.06:206:19
2311.96:226:17
2411.86:246:14
2511.86:266:12
2611.76:276:09
2711.66:296:07
2811.66:316:04
2911.56:336:02
3011.46:355:59

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 2.81 kWh/m².

For context, solar energy here swings from a low near 0.56 kWh/m² to a high of 5.06 kWh/m² in June across the year — September's 2.81 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
13.4Moderate
23.4Moderate
33.3Moderate
43.3Moderate
53.3Moderate
63.2Moderate
73.2Moderate
83.1Moderate
93.1Moderate
103.0Moderate
113.0Moderate
123.0Moderate
132.9Moderate
142.9Moderate
152.9Moderate
162.8Moderate
172.8Moderate
182.7Moderate
192.7Moderate
202.7Moderate
212.6Moderate
222.6Moderate
232.5Moderate
242.5Moderate
252.4Moderate
262.4Moderate
272.3Moderate
282.3Moderate
292.3Moderate
302.2Moderate
Planning a trip in September

Is September a good time to visit Carlow?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

4.8
Sightseeing
4th-best month of the year
0.9
Beach & pool
4th-best month of the year

September is a reasonable time to visit Carlow for sightseeing.

What to pack for Carlow in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Carlow sees daytime highs around 16°C and nights near 10°C. Worth packing: a warm layer and rain gear. About 11 days see rain.

a warm layerrain gear

Sea temperature near Carlow in September

The nearest coast averages about 15°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 54 km away) is warmest in September at about 15°C and coldest in March near 8°C.

The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.

10°15°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°C)Comfort
Jan9Bracing
Feb8Bracing
Mar8Bracing
Apr9Bracing
May10Bracing
Jun12Bracing
Jul14Bracing
Aug15Cool
Sep15Cool
Oct14Bracing
Nov12Bracing
Dec11Bracing

UV index in Carlow in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Carlow peaks around August 13 at about 6 (high) — a little sun protection helps at midday. It bottoms out near January 1 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 6 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowAug 13UV 6Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar3Moderate
Apr4Moderate
May5High
Jun6High
Jul5High
Aug6High
Sep4Moderate
Oct2Moderate
Nov1Low
Dec1Low
Location & terrain

Where is Carlow?

Carlow sits at 52.8°N, 6.9°W, 55 m above sea level, in Ireland. The nearest listed city is Kilkenny, 30 km away.

KilkennyPortlaoiseDroichead NuaNaasTullamoreCelbridgeTallaghtSouth Dublin

Topography around Carlow

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Carlow.

Within 3 km, the terrain around Carlow has only modest variations in elevation — a maximum elevation change of 57 m around an average of 57 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 320 m; within 80 km, large variations in elevation — a maximum elevation change of 933 m.

The land around Carlow is covered by grassland (44%) and cropland (28%) within 3 km, grassland (60%) and cropland (28%) within 16 km, and grassland (64%) within 80 km.

3 km
57 m
16 km
320 m
80 km
933 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Kilkenny 30 km · Portlaoise 33 km · Droichead Nua 39 km · Naas 45 km · Tullamore 61 km · Celbridge 61 km · Tallaght 62 km · South Dublin 63 km

Ireland travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type G
230 V · 50 Hz
Prices
≈ 85% of US
price level, 2025
GDP per capita
$131,592
2025
Happiness
6.9 / 10
World Happiness, 2025
Safe drinking water
96%
of population, 2024
Homicide rate
0.7
per 100k, 2023
Road deaths
3.1
per 100k/yr, 2019
Income group
High
World Bank
Religion
Roman Catholic 69%none 15%Protestant 4%Orthodox 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Carlow (52.8408°, -6.9261°, elevation 55 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).